With development of communications technologies, there have been various formats of network. A Long Term Evolution (LTE) network and a Wireless Fidelity (Wi-Fi) network are two different frequently-used formats of network.
When a terminal is located in a coverage area of the Wi-Fi network and that of the LTE network at the same time, the terminal can access one network, and then communicate with a server by using the network accessed by the terminal. For example, the terminal can access the Wi-Fi network to communicate with the server. However, because network signal energy often changes, the terminal needs to perform signal energy assessment on each to-be-assessed network (for example, the Wi-Fi network or the LTE network) at regular intervals in one energy assessment period (for example, 600 milliseconds). For example, the terminal may perform signal energy assessment on the Wi-Fi network once every 100 milliseconds of 600 milliseconds to obtain one signal energy value of the Wi-Fi network, and perform signal energy assessment on the LTE network once every 100 milliseconds of 600 milliseconds to obtain one signal energy value of the LTE network. If in one energy assessment period, each obtained signal energy value of the Wi-Fi network is less than a preset energy threshold, and each obtained signal energy value of the LTE network is greater than the preset energy threshold, the terminal can determine that signal energy of the Wi-Fi network is weaker and signal energy of the LTE network is stronger. In this case, the terminal can directly disconnect from the Wi-Fi network and access the LTE network.
When to-be-assessed-network signal energy of the terminal changes at a fast speed, the terminal can determine whether the to-be-assessed-network signal energy is strong or weak still after one energy assessment period. Therefore, it takes a relatively long time for the terminal to perform signal energy assessment on the to-be-assessed network, and efficiency in signal energy assessment on the network is relatively low.